This invention relates to a lock for motor vehicle doors, of the type comprising a striker member generally fixed to the motor vehicle body and arranged to be engaged and disengaged by means comprised in a mechanism of said lock, which is substantially housed in the door. In said locks there are generally two positions of snap-engagement, and disengagement can occur either by operating an outer handle or by operating an inner control member. In addition, safety means are generally provided for preventing disengagement (either by way of the inner control means or the outer handle).
Such motor vehicle locks must offer a certain degree of protection against accidental opening, even under the action of large forces, as can occur during collisions. Thus, national and international standards have fixed the load values in a longitudinal and transverse direction (relative to the vehicle) which the lock must be able to resist. In particular, the withstandable transverse load (which is also the load which tends to disengage the means comprised in the lock mechanism from the striker member in the door opening direction) according to the international standards drawn up by the E.C.E. of Geneva must be at least equal to 453 Kgf in the first closure position, and 907 Kgf in the total closure position. The withstandable longitudinal load must be at least equal to 453 Kgf in the first closure position, and 1134 Kgf in the total closure position.
In known locks, the engagement between the striker member and the means comprised in the lock mechanism is generally obtained by forks. However, the disengaging load exerted between said striker member and the other parts of the lock mechanism, and generally acting in a transverse direction, can assume a very high value under the action of a violent impact following collision, and generates moments through said fork which have to be sufficiently opposed by the mechanism parts of the lock. In order to ensure proper safety even against stresses under very critical conditions, these known locks must be sized such that the various component pieces are of sufficient strength, and this leads to relatively large bulk.